Methane mitigation strategy for food waste management: Balancing socio-economic acceptance and environmental impacts

Studies on food waste management are focused on specific technologies at various extents, such as landfill, anaerobic digestion, and composting, whereas few concern dietary, socioeconomic and environmental factors together to evaluate different technologies from a global perspective. This study aims to fill this knowledge gap. Life cycle assessment of food waste treatment baseline scenario (based on national technology market shares as of 2017) and 5 methane mitigation scenarios, including SEM scenario (considering solely economic mitigation effort echoed by social discount rate), LF-70 % scenario (landfill (LF) substituting 70 % of dumpsite disposal (DSD) market share), COM-70 % scenario (composting (COM) substituting 70 % of the market share for LF and DSD) (5) IC-70 % scenario (incineration (IC) substituting 70 % of the market share for LF and DSD), and AD-70 % scenario (anaerobic digestion (AD) substituting 70 % of the market share for LF and DSD), was carried out based on dataset from Food and Agriculture Organization of the United Nation. The global warming potential was highly skewed to non-perishable food (0.82 Gt CO2 equivalent), accounting for nearly 3 quarters of greenhouse gas (GHG) emissions for the entire food waste management in 2017 (1.1 Gt CO2). Food waste GHG emissions are inversely proportional to technology levels. It is therefore vital to optimize the technology choice in the nexus of specific food waste category and the development status of different countries or regions for effective food waste GHG emission reductions. Considering various dietary choices, together with future development of economy and demography, food waste GHG emission trajectory was projected with a modified Regional Integrated model of Climate and the Economy model. 85.8–88.0 % GHG emission reductions are expected by 2100 across all methane mitigation scenarios though, AD demonstrates multiple additional environmental benefits. Nonetheless, it faces the dilemma of low market penetration globally due to high technological requirements. In this regard, alternative technology selections, such as composting, need to be combined with local social context to achieve a steady and tangible FW GHG emission reduction effect.